/Engine/Source/Editor/UnrealEd/Public/FileHelpers.h
Looks at all currently loaded packages and saves them if their "bDirty" flag is set. Prompt the user to select which dirty packages to save and check them out from source control (if enabled).
true on success, false on fail.
static bool SaveDirtyPackagesWithDialog ( const bool bSaveMapPackages, const bool bSaveContentPackages )